The proposed research program is designed to investigate areas of current bio-medical importance and at the same time provide Puerto Rico students with the opportunity to acquire research skills. The directorate of Inter American University of Puerto Rico supports the objectives of the planned research and the goals of the Minority Biomedical Research Support Program. The proposed projects are: 1) Synthesis and Biological Activity of Azaoxspi-ranes; New chiral spirohetherocyclic compounds are synthesized and tested for cell membrane activity. Particular emphasis will be given to the stereochemistry-activity relationship. 2) Opportunistic Parasites and Their Control by Polyamine Inhibition; A survey of a segment of the animal population in Puerto Rico for presence of Pneumocystis carinii and Cryptosporidium spp. will be conducted. The role of polyamine inhibition as a means of control will be explored. 3) An Instrument for Epidemiological Studies on Alzheimer's Disease in a Hispanic Population; Development of an instrument and conducting an epidemiological study to assess incidence of Alzheimer's disease in a sample of the Hispanic population in Puerto Rico. 4) Airborne Mutagens as Contaminents of Water Reservoirs; A relationship between airborne mutagens and mutagens found in water reservoirs in Puerto Rico. 5) Snails Hosts of Human Infecting Parasites; Study of the genetics of Biomphalaria glabrata susceptibility to Schistosoma mansoni. 6) Bacteriological Quality and Pathogenic Potential of Selected Puerto Rican Foods; This investigator will correlate the presence of several food-borne pathogens with the increasing prevalence of gastrointestinal illnesses in Puerto Rico. 7) The Associate Investigators project is: Receptor - Ion Flux and Electrophysical Studies. Here using electrophysical experiments, the positive modulation of cholinergic receptors is studied. These investigators are prepared to fulfill their research commitments and meet the MBRS goals and thus make a contribution to biomedical science through research and training of students who will want to pursue research careers.